1. Field of the Invention
The present invention relates to damper components of the type for reducing or eliminating the resonation of vibration and/or noise, and to methods for making and using damper components.
2. Description of the Related Art
Unsaturated polyester sheet molding compounds, also known in the art and referred to herein as “SMCs,” have physical properties and ease of processability that have made the materials popular in the production of a wide array of goods. For example, SMCs are found in parts of household appliances, motor vehicles, computer disk drives, and other apparatuses and devices having moving parts that generate vibration and noise. SMC are also found in generally static articles, such as in walls, siding, and doors of residential and commercial buildings and construction.
SMCs possess some capacity to absorb and dissipate vibration and noise resonating from a proximal source. However, SMCs are sometimes deemed to lack sufficient vibration-damping and noise-damping properties for certain situations requiring a high degree of vibration and noise insulation.
Viscoelastic materials are known for their ability to absorb and dissipate vibrational energy and to damp associated noise and vibration. In use, a viscoelastic material is typically applied directly to devices that emanate/resonate noise and vibration. The viscoelastic materials are bonded to or otherwise operatively associated with a device as a “free layer,” that is, as a one-layer structure. Viscoelastic materials need not be used in isolation. For example, a substrate may be placed on one surface of a viscoelastic layer to form a composite, which may then be bonded to or otherwise operatively associated with a device so that the viscoelastic layer is bonded to or faces the structure. It is known to incorporate viscoelastic materials in structural laminates comprising a pair of metallic sheets (or metallic skins) sandwiching the viscoelastic material, as disclosed as an embodiment in U.S. Pat. No. 6,202,462 to Hansen et al., assigned to the same assignee of this application. The laminate metallic skins between which the viscoelastic material is placed are known as constraining layers.
Each of the aforementioned viscoelastic materials and composites has drawbacks. In many of the above-described embodiments, the viscoelastic material is placed in direct contact with the device to be damped. As a consequence, the viscoelastic layer and optionally an attached substrate must be molded or otherwise shaped to match the surface contours of the device. However, viscoelastic layers and metallic skins generally lack sufficient moldability or malleability to allow them to be fabricated for and placed in continuous intimate contact with vibration/noise-resonating devices having complex shapes.
The aforementioned free viscoelastic layer and composite have additional drawbacks associated with their methods of use. Typically, a free viscoelastic layer or a composite is either attached to the outer surface of the device to be damped or is installed in a housing of the device. In both instances, the damper constitutes an additional structure that otherwise would not be present, thereby imposing weight and space penalties. For example, depending upon the location of the damper, added space must be afforded inside or outside of the device's housing to receive the damper. Manufacturing time and costs are also increased by the addition of a damper structure to a vibrating or noise resonating device or structure.
Additionally, placement of damper layers on a device or structure may create design tradeoffs. For example, complex shapes are often not amenable to add-on treatments. Accordingly, parts or portions of a vibrating/noise-resonating device or structure that are not or cannot be associated with a damper layer, for example, due to the complex shape of the device or structure, can adversely affect dampening effectiveness.
Accordingly, it would be a significant improvement in the art to provide a damper component that replaces an existing component of the damped device to thereby eliminate or at least alleviate the imposed weight and space penalties, preferably while avoiding the need for compromising design tradeoffs.
3. Objects of the Invention
Accordingly, it is an object of the present invention to provide a damper component that is readily formable into a desired shape, including a complex shape, for permitting placement of the damper component in intimate contact with a vibration/noise-emanating device or structure.
It is another object of the present invention to provide a damper component that may replace an existing component of a device or structure to be damped and thereby achieve a significant improvement in the art over known dampers.
It is another object of the present invention to provide methods for making a damper component, including methods for making damper components that achieve one or more of the above-discussed objects.
It is a further object of the present invention to provide a device comprising a damper component, in which the damper component replaces an existing structure as a functional or structural component of the device.
It is still a further object of the present invention to provide a method for retrofitting an existing structure or device to replace an existing component with a damper component having a substantially identical shape and/or appearance to the existing component.